This article presents the results of studies on the selection of excipients for the production of efavirenz encapsulated mass using the 5x5 two-factor analysis of variance method with repeated observations (n=30). According to the results obtained for the encapsulated mass of efavirenz, the use of a mixture of microcrystalline cellulose and lactose as a filler, and croscarmellose sodium as a disintegrator, has been scientifically substantiated. The selection of the antifriction substance was carried out based on the results of studying such pharmacotechnological indicators as flowability and angle of repose. It has been ascertained that the use of magnesium stearate provides the mass with the necessary flowability index to obtain high-quality products. Based on the selected composition, a technology for producing capsules has been developed, which has been tested in industrial conditions.